Shaped charge with rotational insert



Sept. 1, 1964 Filed May 20, 1959 F. SCHAADT ETAL 3,146,711

SHAPED CHARGE WITH ROTATIONAL INSERT 3 Sheets-Sheet 1 Inventors $5.4X44... m1

(a/whim Kla waz. M, y/wz q man Sept. 1, 1964 F. SCHAADT ETAL 3,146,711

SHAPED CHARGE WITH ROTATIONAL INSERT Filed May 20, 1959 3 Sheets-Sheet 2[vi enters M jAda 4 v p 1954 F. SCHAADT ETAL SHAPED CHARGE WITHROTATIONAL INSERT 5 Sheets-Sheet 3 Filed May 20, 1959 United StatesPatent Ofiice This invention relates to an explosive device having meansfor propelling and effecting the rotation of an insert.

According to the present invention, an explosive device includes ahollow charge having an insert on which, by means of the arrangement ofthe explosive, a tangential component of velocity is impressed upondetonation of the explosive charge such that the insert is caused torotate as it is propelled.

The tangential component of velocity may be created by suitably shapingthe insert or by suitably shaping the front of the blast wave producedwhen the explosive charge is detonated.

The propelled insert can then be used in numerous ways for both militaryand also civil purposes, namely:

(a) Directly as a combat weapon, for example as an incendiary projectilefor use against fast missiles, low flying aircraft, armoured vehiclesand the like;

b) Indirectly to accelerate and stabilize other objects, for exampleprojectiles contained inside the insert. A rotation is in this wayobtained according to the invention which not only imparts to the saidprojectiles a high starting velocity which could not be achieved in anyother manner, but which gives them also the spin which is necessary forstable free flight;

(c) For many purposes of non-military engineering, for example blastingand enlarging holes into rock and other hard materials, particularlyholes of larger diameters.

Embodiments of the invention will now be described, by way of exampleonly, with reference to the accompanying drawings, of which,

FIG. 1 shows a diagram to explain the rotational effect by reference toa plan view of an insert consisting of a stepped cone having six stepsin which the external surfaces of the stepped cone are bounded by arcsof circles.

FIG. 2 shows a diagram corresponding to FIG. 1 but with the surfaces ofthe stepped cone bounded by spirals,

FIGS. 3 and 4 show an insert in the form of a stepped cone of anon-rotating hollow charge with the neighbouring portions after thecharge has been detonated, FIG. 3 being a longitudinal section and FIG.4 a plan,

FIGS. 5 and 6 show a hollow charge, with a secondary projectile mountedinside the insert, which has the shape of a stepped cone, before thedetonation, in side view and plan, and

FIGS. 7 and 8 show a hollow charge corresponding to FIG. 5 during twostages after detonation.

As shown in FIG. 1 the insert 1 is provided with six steps a to 1similar to a ratchet wheel, the steps being bounded by circular arcs 2.The edges of the separate steps connecting them to the apex of the conehave been omitted to assist clarity of the drawing.

When the explosive charge is detonated the separate particles 3 of theinsert travel in the direction of the arrows 4. These arrows convergetowards the centre of curvature of the relevant circular are asindicated at 5. The resultant of these arrows is therefore representedapproximately by the arrow 6, i.e. approximately tangential to thecircle 7a and accordingly a rotational effect is imparted as representedby the arrows 6 to 11.

In the embodiment shown in FIG. 2 the position is the 3,145,711 PatentedSept. 1, 1964 same except that here the surfaces 12 bounding the insert13 form part of a spiral or helix. This has the advantage thatpractically every particle moves in a direction tangential to the circle7a resulting in a more homogenous process.

FIG. 3 shows a solid elongated spike like member 15 and striker 16attached to an insert 14. Due to the fact that the insert 14 has theform of a stepped cone, the spike 15 and the striker 16 are set inrotation.

Instead of a stepped cone, it is possible to use any one of the othershapes of insert disclosed in application Serial No. 791,882, filedFebruary 9, 1959, now abandoned, in order to produce a tangentialvelocity component and hence a rotational effect.

For example, the insert may be a spiral cone which may be considered tobe formed by winding the insert of FIGS. 1 and 2 to produce spiralsteps, the edges of which have an angle of twist other than zero. Thistype of insert can be made by winding a strip of sheet metal.

Alternatively, as described in application Serial No. 791,882, filedFebruary 9, 1959, now abandoned, the insert may comprise a normalcircular cone and the tangential component of velocity produced bydetonation of a suitably shaped explosive capsule inserted in theexplosive charge, the capsule having a speed of detonation which differsfrom that of the normal explosive charge. An additional explosivecapsule having a lens shape may also be provided, this additionalcapsule also having a speed of detonation which differs from that of thenormal explosive charge.

The effect obtainable by virtue of the rotation according to theinvention is illustrated in FIGS. 5 to 7; here the insert 17 has theshape of a truncated stepped cone inside which a secondary projectile 18is located and which is firmly attached to the insert 17. The projectile18 is provided with grooves or rifling 19 in order to offer a moreeffective surface to the particles approaching it tangentially upondetonation. The grooves 19 make an angle 20 with the longitudinal centreline of the projectile. 21 designates the usual explosive charge and 22the fuse. The outer shell of the hollow charge is shown at 23.

As will be seen on comparing FIGS. 5, 6 and 7, in addition to thespinning velocity 24 a high axial acceleration in the direction of thearrow 25 is also impressed upon the secondary projectile 18 when thecharge 21 is detonated so that there are quite new possibilities, bothmilitary and non-military, for the hollow charge as described above, inwhich the temperature of the effective rotating solid jet is probablyalso of considerable significance.

What we claim is:

1. A hollow charge explosive device comprising a casing with anexplosive charge with a hollow space in the explosive charge, asubstantially funnel-shaped inert longitudinally disposed in the deviceto serve as a lining for the hollow space, said insert having Workingsurfaces which are so shaped that during the detonation of the explosivecharge a tangential component of force is imparted by the detonationpressure to the parts of the material of the insert to cause the insertto rotate as it is propelled, said insert being shaped as a stepped conehaving surface steps, as viewed in cross-section in a plane at rightangles to the longitudinal axis of the cone, interconnected with curvedboundary lines as generating surfaces, the curvatures of the boundarylines being so arranged and so formed that their centers follow eachother on a circle around the longitudinal axis of the cone, a projectileprovided in the insert and which is an elongated spike-like object, andat least part of the surface of the insert is provided with grooveshaving an angle of twist.

2. A hollow charge explosive device comprising a casing with anexplosive charge with a hollow space in the explosive charge, asubstantially funnel-shaped insert longitudinally disposed in the deviceto serve as a lining for the hollow space, said insert having workingsurfaces which are so shaped that during the detonation of the explosivecharge a tangential component of force is imparted by the detonationpressure to the parts of the material of the insert to cause the insertto rotate as it is propelled, said insert being shaped as a stepped conehaving surface steps, as viewed in cross-section in a plane at rightangles to the longitudinal axis of the cone, interconnected with curvedboundary lines as generating surfaces, the curvatures of the boundarylines being so arranged and so formed that their centers follow eachother on a circle around the longitudinal axis of the cone, a projectileprovided in the insert and which is an elongated spike-like object, andat least part of the surface of the insert is provided with roughedportions having an angle of twist.

3. A hollow charge explosive device comprising a casing with anexplosive charge therein, with a hollow space in the explosive charge, asubstantially funnel-shaped insert longitudinally disposed in the deviceto serve as a lining for the hollow space, said insert having workingsurfaces which are so shaped that during the detonation of the explosivecharge a tangential component of force is imparted by the detonationpressure to the parts of the material of the insert to cause the insertto rotate as it is propelled, said insert being shaped as a cone of astepped spiral form having surface steps, as viewed in cross-section ina plane at right angles to the longitudinal axis of the cone,interconnected with curved boundary lines as generating surfaces so thatthe centers of the curvatures follow each other on a circle around thelongitudinal axis ll. of the cone, a projectile provided in the insertand which is an elongated spike-like object, and at least part of thesurface of the insert is provided with grooves having an angle of twist.

4. A hollow charge explosive device comprising a casing with anexplosive charge therein, with a hollow space in the explosive charge, asubstantially funnel-shaped insert longitudinally disposed in the deviceto serve as a lining for the hollow space, said insert having workingsurfaces which are so shaped that during the detonation of the explosivecharge a tangential component of force is imparted by the detonationpressure to the parts of the material of the insert to cause the insertto rotate as it is propelled, said insert being shaped as a cone of astepped spiral form having surface steps, as viewed in cross-section ina plane at right angles to the longitudinal axis of the cone,interconnected with curved boundary lines as generating surfaces so thatthe centers of the curvatures follow each other on a circle around thelongitudinal axis of the cone, a projectile provided in the insert andwhich is an elongated spike-like object, and at least part of thesurface of the insert is provided with roughed portions having an angleof twist.

References Cited in the file of this patent UNITED STATES PATENTS2,238,939 Lewis et al. Apr. 22, 1942 2,326,310 Johnson et al Aug. 10,1943 2,796,833 Sweetman June 25, 1957 2,856,850 Church et a1 Oct. 21,1958 2,887,953 Mager May 26, 1959 FOREIGN PATENTS 447,121 Canada Mar. 9,1948 1,077,914 France May 29, 1953

1. A HOLLOW CHARGE EXPLOSIVE DEVICE COMPRISING A CASING WITH ANEXPLOSIVE CHARGE WITH A HOLLOW SPACE IN THE EXPLOSIVE CHARGE, ASUBSTANTIALLY FUNNEL-SHAPED INERT LONGITUDINALLY DISPOSED IN THE DEVICETO SERVE AS A LINING FOR THE HOLLOW SPACE, SAID INSERT HAVING WORKINGSURFACES WHICH ARE SO SHAPED THAT DURING THE DETONATION OF THE EXPLOSIVECHARGE A TANGENTIAL COMPONENT OF FORCE IS IMPARTED BY THE DETONATIONPRESSURE TO THE PARTS OF THE MATERIAL OF THE INSERT TO CAUSE THE INSERTTO ROTATE AS IT IS PROPELLED, SAID INSERT BEING SHAPED AS A STEPPED CONEHAVING SURFACE STEPS, AS VIEWED IN CROSS-SECTION IN A PLANE AT RIGHTANGLES TO THE LONGITUDINAL AXIS OF THE CONE, INTERCONNECTED WITH CURVEDBOUNDARY LINES AS GENERATING SURFACES, THE CURVATURES OF THE BOUNDARYLINES BEING SO ARRANGED AND SO FORMED THAT THEIR CENTERS FOLLOW EACHOTHER ON A CIRCLE AROUND THE LONGITUDINAL AXIS OF THE CONE, A PROJECTILEPROVIDED IN THE INSERT AND WHICH IS AN ELONGATED SPIKE-LIKE OBJECT, ANDAT LEAST PART OF THE SURFACE OF THE INSERT IS PROVIDED WITH GROOVESHAVING AN ANGLE OF TWIST.